Straddle latch needle

ABSTRACT

This is a latch type element for use in knitting machines. The latch is externally mounted to avoid manufacturing and operational problems experienced with conventional slot mounted latched knitting machine elements.

Unlted States Patent I 1 1 1 3,728,874 Kell et al. 1 A r. 24, 1973 [541 STRADDLE LATCH NEEDLE l,730,546 10/1929. Van Dyke ..66/l2l x [7 1 In en Robert R y; J p P FOREIGN PATENTS OR APPLICATIONS jens, both of Torrington, Conn.

105,316 4/1917 GreatBritain ..66/l2l [73] Ass1gnee: The Tornngton Company, Torrmgton, Conn. I

Primary Examiner-Ronald Feldbaum [22] Filed: Aug. 19, 1971 Attorney-Frank S. Troidl et a1.

21 A 1.N 173,040 1 pp 57 ABSTRACT 52 U.S. c1 ..66/l21 This is a latch type element for use in knitting [51] Int. Cl. ..D04b 35/04 machines- The latch is externally "wumed 58 Field of Search ..66/1l6, I21, I22, manufacturing and Operational Problems experienced 123 124 with conventional slot mounted latched knitting machine elements. [5 6] References 15 Claims, 8 Drawing Figures UNITED STATES PATENTS 3,526,104 9 1970 Beighton etal. ..66/l22 v PAIENTEDAPR 24 1975 u 5 m 2 m u 4 m m6 m mF 4 v 3 w 2 3 w m 3 B 0w 0 F v ..,.s 6a a .m m m m 0 FIG. 7

- ROBERT F. KELLY JOSEPH Z' SPEETJE/VS STRADDLE LATCH NEEDLE BACKGROUND OF THE INVENTION This invention relates to knitting machine elements. More particularly, the invention is a new and improved latch type needle for use in knitting backing for tufted carpeting or circular knitted fabrics.

The common latch needle may be described as a piece of material, usually steel, ending in a hook and provided near the hook with a pivotally mounted part called a latch. The latch, when turned toward the hook the fullest amount, covers the hook and shields any yarn engaged therein. When fully turned the opposite way, the latch leaves the hook exposed. The latch, thus, is a rotatable member pivotally attached to the needle at one end. Traditionally, the stem of the needle has been provided with a slot or groove in which a thinly pressed latch is inserted and pivoted.

Several problems have resulted from this slot construction. The sides of the slot may spread apart mak ing the latch too loose. The latch tends to spread the ,groove ocassionally causing breakage. Dirt may be caught in the groove in sufficient quantities to interfere with the proper action of the latch. The support area available to the pivot is limited to the thickness of the latch. The sides of the groove usually cut with tooth cutters, are not perfectly smooth. Also, the groove may be closed too tightly, causing the latch to bind and impair proper action.

We have invented an improved latch needle in which a groove is replaced by a projection and the latch straddles this projection. If the projection is symmetrical to the needle body, the latch would be bifurcated. In another embodiment, the projection would be asymmetrical, and the latch would have a complementary slab located on one side of the protrusion only.

The pivot upon which the latch turns may be of several types, rivet, screw, or projection from one of the elements. A projecting pivot may be welded, raised, or be of the material of either the projection or the latch itself, a type known in the trade as an agula pivot.

By eliminating the groove in the needle, the attendant problems are also eliminated. While the foregoing has described the invention as a needle, it is to be understood that this invention is not limited to application with knitting needles as there are other machine elements with latches to which this concept can be applied.

BRIEF DESCRIPTION OF THE DRAWINGS In the following description and claims, parts will be identified by specific names which are intended to be generic in their application to similar parts. Like reference characters denote like parts in the several views of the invention in which:

FIG. 1 is a perspective view of the hook end of a bifurcated straddle latched knitting machine element;

FIG. 2 is a partial perspective view of a knitting element with an asymmetrical straddle latch and pivot section; and

FIGS. 3 8 show the sequential steps in the operation ofa latch type needle.

Referring particularly to FIGS. 1 and 2, it can be seen that the knitting machine element has a body 10 with a hook 12 at one end. A pivot section 14 proximate to the hook supports a latch 16 which is moveably mounted on the pivot section by a pivot 18. The free end 20 of the latch will rest on the hook 12 when the latch is in the closed position.

For better alignment and stability, a noucat 22 may be indented in the free end of the latch. A noucat is defined as the spoon-like end of the latch opposite the pivoted end. On the opposite side from the noucat, the latch has an arcuate surface 24 to facilitate stress and strain free movement of a knitted loop over that surface while the latch is in the closed position, and to enable a loop moving from the body toward the hook and off the needle to flip an open latch into the closed position. The pivot section similarly has a curved surface 26 to permit stress-free movement of a loop from the hook rearward and to facilitate opening of the latch during this movement in the knitting cycle. The width of the bifurcated straddle latch illustrated in FIG. 1, or the combined width of the asymmetrical latch and its corresponding pivot slab 28 visible in FIG. 2 are equal to or less than the thickness of the body of the machine element in order to avoid snagging or stretching of the knitted loop.

FIGS. 3 to 8 show the operation of the needle in the knitting cycle. While an old loop of the thread 30 is positioned on the retaining area 32 of the needle in FIG. 3, a new loop 34 is engaged by the hook 12. As the latch needle moves toward the right in FIGS. 4 6, the old loop slides leftward engaging the underside of the latch flipping it over the hook thereby permitting the old loop to slip over the hook and the new loop which is engaged therein. When the new loop has been pulled through the old loop, as in FIG. 6, the direction of needle movement is reversed and the new loop slides to the retaining area 32 of the needle simultaneously opening the latch FIG. 7 and exposing the hook to receive another new loop. The curved surfaces 24 and 26 reduce strain and stress on the thread being knitted. 1

We claim:

1. A knitting machine element comprising:

a body;

a hook at one end of the body;

a solid pivot section emerging upwardly from the body near the hook;

pivot means extending outwardly from the solid pivot section; and

a latch pivotably engaged at one end by the pivot means to the pivot section to abut the free .end with the outside of the hook when the latch is in the closed position.

2. The knitting machine element of claim 1 wherein the pivot section further comprises a longitudinally symmetrical projection from the body.

3. The knitting machine element of claim 2 wherein the latch is bifurcated, and straddles the pivot section.

4. The knitting machine element of claim 3 wherein the latch further comprises a noucat positioned at the free end to abut the hook when the latch is in the closed position.

5. A knitting machine element of claim 4 wherein the latch has an arcuate shape on the side opposite the noucat.

6. A knitting machine element of claim 5 wherein the pivot means comprises aligned apertures in the pivot section and latch, and a partially cylindrical member cooperatively inserted therethrough.

7. The knitting machine element of claim 5 wherein the pivot means comprises an aperture in the pivot section and agula pivots inwardly directed thereto from the bifurcated end of the latch.

8. The knitting machine element of claim 5 wherein the pivot means comprises apertures in the bifurcated end of the latch and projections outwardly directed thereinto from the pivot section.

9. The knitting machine element of claim 1 wherein latch is further characterized by having a noucat at the free end to abut the hook in the closed position.

l2. The knitting machine element of claim 11 wherein the latch is further characterized by having an arcuate shape on the side opposite the noucat.

13. The knitting machine element of claim 12 in which the pivot means further comprises aligned apertures in the pivot section and latch, and a partially cylindrical member cooperately inserted therethrough.

14. The knitting machine element of claim 11 wherein the pivot means comprises an aperture in the latch, and a projection directed thereto from the pivot secton.

15. The knitting machine element of claim 11 wherein the pivot means comprises an aperture in the pivot section and a projection directed therethrough from the latch. 

1. A knitting machine element comprising: a body; a hook at one end of the body; a solid pivot section emerging upwardly from the body near the hook; pivot means extending outwardly from the solid pivot section; and a latch pivotably engaged at one end by the pivot means to the pivot section to abut the free end with the outside of the hook when the latch is in the closed position.
 2. The knitting machine element of claim 1 wherein the pivot section further comprises a longitudinally symmetrical projection from the body.
 3. The knitting machine element of claim 2 wherein the latch is bifurcated, and straddles the pivot section.
 4. The knitting machine element of claim 3 wherein the latch further comprises a noucat positioned at the free end to abut the hook when the latch is in the closed position.
 5. A knitting machine element of claim 4 wherein the latch has an arcuate shape on the side opposite the noucat.
 6. A knitting machine element of claim 5 wherein the pivot means comprises aligned apertures in the pivot section and latch, and a partially cylindrical member cooperatively inserted therethrough.
 7. The knitting machine element of claim 5 wherein the pivot means comprises an aperture in the pivot section and agula pivots inwardly directed thereto from the bifurcated end of the latch.
 8. The knitting machine element of claim 5 wherein the pivot means comprises apertures in the bifurcated end of the latch and projections outwardly directed thereinto from the pivot section.
 9. The knitting machine element of claim 1 wherein the pivot section further comprises a slab asymmetrically projecting from the body.
 10. The knitting machine element of claim 9 wherein the latch further comprises a slab having a thinner section at one end dimensioned to cooperate with the pivot section slab and result in a total combined slab thickness no greater than the body thickness of the machine element.
 11. The knitting element of claim 10 wherein the latch is further characterized by having a noucat at the free end to abut the hook in the closed position.
 12. The knitting machine element of claim 11 wherein the latch is further characterized by having an arcuate shape on the side opposite the noucat.
 13. The knitting machine element of claim 12 in which the pivot means further comprises aligned apertures in the pivot section and latch, and a partially cylindrical member cooperately inserted therethrough.
 14. The knitting machine element of claim 11 wherein the pivot means comprises an aperture in the latch, and a projection directed thereto from the pivot section.
 15. The knitting machine element of claim 11 wherein the pivot means comprises an aperture in the pivot section and a projection directed therethrough from the latch. 